1. Field of the Invention
The present invention relates to a structure for connecting a lead wire (a power supply wire) and a heater wire to each other and, more particularly, to a connection structure for a lead wire and a heater wire for use in a pipe joint or the like.
2. Description of the Related Art
Such a connection structure for a lead wire and a heater wire is disclosed in, for example, Japanese Published Unexamined Patent Application No. 2005-351333.
In this connection structure, as shown in FIG. 6, a lead wire LW and a heater wire HW are connected to each other (at a connecting section t) by inserting the lead wire LW into a cap member 90 and inserting the heater wire HW into another cap member 91, then a female screw 92 and a male screw 93 in the cap members 90 and 91 are screwed with each other, and subsequently, the male screw 93 is screwed into a pipeline 96, whereby O-rings 94, 95 and 97 prevent any liquid from leaking into the connecting section t.
However, this connection structure for the lead wire LW and the heater wire HW poses the following problems:
(1) since the diameter of the cap members 90 and 91 tends to be relatively large, a considerably large space is required for connecting a plurality of lead wires LW to a plurality of heater wires HW;
(2) after connecting the lead wire LW and the heater wire HW to each other, the cap member 90 and the cap member 91 always have to be screwed together and this is a cumbersome work; and
(3) there may occur an unfavorable situation in which the lead wire LW and the heater wire HW are twisted due to a contact resistance with the O-rings 94 and 95 in screwing the cap members 90 and 91 with each other: namely, breakage may be caused by torsion if the wires are weak.
In view of this, engineers in this field desperately wish development of a connection structure for a lead wire and a heater wire which needs only a small space, has excellent workability, and causes no twisting of the lead wire LW and the heater wire HW.